I want to make a histogram using some JavaScript charting library but the data has over 1 million numbers. I would retrieve the data via an Ajax call and draw it using something like jqPlot but I wonder if anyone ever did any performance testing with trying to create a chart with a lot of data.

Are you plotting all those values or using their averages (or other aggregate value) ? If it's the latter then I'd suggest calculating it on the server first.
–
Lee TaylorAug 9 '12 at 17:29

Yeah, I do think that I will have to do some of the work on the server side but I am wondering what would happen if I did it all on client side? How many numbers would cause what kind of latency? Just wondering if anyone ran a test before I do it myself...
–
iwekAug 9 '12 at 17:39

The server is a known quantity. The client may be running very old kit and throwing a million numbers at it would probably be painful. I'd suggest trying to do as much as possible on the server.
–
Lee TaylorAug 9 '12 at 18:06

One thing you could try is only fetching the data you need to display immediately. I.e. if you are 'zoomed out', and only need to show, say, days, you wont need that many. And if you 'zoom in' to a section, say of a couple of months, you could, using AJAX, only then load the data (and then cache it locally).
–
andrewmuAug 10 '12 at 9:41